Electrical question

A

Adam P

Well-known member
The other day I was playing my bass in the room of my house that I eventually would like to make into my "control room" (it is an upstairs bedroom). I was plugged into my SansAmp, which is powered by a wall wart power supply. The outlet it was plugged into is not grounded (my house is older) but does have a GFCI installed. At one point I had my right hand on the strings of the bass and reached up to turn on the ceiling fan with my left. When I did this I got a little zap...it didn't hurt but it did startle me. It wasn't enough to trip the GFCI either.

Would this be indicative of a ground fault in the electrical outlet I was plugged into, causing the circuit to ground through me to the ceiling fan when I touched it? Could this outlet be grounded to a cold water pipe, or would that mean the ground fault was being sent to the water pipe, making the pipe hot?

I'd like to get this rectified ASAP...thanks in advance.
 
Sounds to me like your ceiling fan is wired incorrectly. No exposed metal part should be hot. I strongly recommend that you have someone who knows how to use a voltmeter check the ceiling fan against ground ASAP.

It is possible that the bass strings were hot, but it seems more likely to me that the ceiling fan is at fault.

You really ought to have an electrician take a look at it before it's too late.
 
Adam P said:
`The outlet it was plugged into is not grounded (my house is older) but does have a GFCI installed. .
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wrong !!! without a ground (safety) the gfci is useless... actually inoperable !!!

do you own or rent?? if the former get a good electrician to at least wire the studio room right...
 
dementedchord said:
wrong !!! without a ground (safety) the gfci is useless... actually inoperable !!!

do you own or rent?? if the former get a good electrician to at least wire the studio room right...
Click to expand...

...and if the latter...kick yer landlord in the pants to upgrade the electrical to code!!!! Sheesh, not safe!!!!
 
DonF said:
Sounds to me like your ceiling fan is wired incorrectly. No exposed metal part should be hot. I strongly recommend that you have someone who knows how to use a voltmeter check the ceiling fan against ground ASAP.

It is possible that the bass strings were hot, but it seems more likely to me that the ceiling fan is at fault.

You really ought to have an electrician take a look at it before it's too late.
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Thanks...I hadn't considered that it might be the fan. I think I'm going to contact the local electrical inspector and ask for a recommendation for an electrician.

dementedchord said:
wrong !!! without a ground (safety) the gfci is useless... actually inoperable !!!
Click to expand...

Actually, that's not true, unless you know something that the NEC doesn't.

NEC § 406.3(D)(3)(b) said:
Where no grounding means exists at an outlet box, a non-grounding receptacle may be replaced with a grounding-type GFI receptacle with no ground connection. The receptacle must be marked "No Equipment Ground". If the GFI protects additional loads, a ground wire must not be connected to the supplied loads.
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All of the GFCIs in my house were installed by a qualified electrician.
 
well maybe one of our electrician types around here will comment to clarify this... my understanding is that they way thet work is by acting as a hair trigger to send the overloaded current to the safety... so no safety... no added protection... yes they will physicly fit the box... and operate as far as passing the AC along but will not operate in the sense of that added protection... and hense my comment... and would assume in your post that the need to mark them as not haveing a ground is indicative of this... but i am open to more data if anyone knows...
 
dementedchord said:
wrong !!! without a ground (safety) the gfci is useless... actually inoperable !!!

do you own or rent?? if the former get a good electrician to at least wire the studio room right...
Click to expand...

You are mistaken - in fact the NEC specifically allows the installation of GFCI recptacles in 2 wire systems.

The following is takke from the site of Mike Holts website.

Replacing Receptacles to Meet the NEC

The NEC requires receptacles installed on 15 and 20 ampere branch circuits to be of the grounding-type and it requires the grounding contacts of those receptacles to be effectively grounded to the branch circuit equipment grounding conductor [210-7]. However, the Code allows the installation of any of the following installations when replacing a 2-wire nongrounding-type receptacle where no ground exists in the outlet box [210-7(d)(3)], Figure 9/10:

(a) Replace the 2-wire receptacle with another 2-wire receptacle.

(b) Replace the 2-wire receptacle with a GFCI-type receptacle and marked the receptacle with the words “No Equipment Ground.”

(c) Replace the 2-wire receptacle with a grounding-type receptacle where protected by a GFCI protection device (circuit breaker or receptacle). Since the grounding terminals for the receptacles are not grounded, the receptacles must be marked with the words “GFCI Protected” and “No Equipment Ground.”

A grounding-type receptacle that is GFCI protected without an equipment grounding conductor is a safer installation than a grounding-type receptacle with an equipment grounding conductor (if GFCI protection is not provided). This is because the GFCI protection device will clear a ground-fault when the fault-current is 5 milliamperes (+ or – 1 milliampere), which is less than the current level necessary to cause serious electric shock or electrocution, Figure 10/11.

A grounding-type receptacle without a ground is a safe installation as long as the GFCI protection circuitry within the device has not failed from shorts and voltage transients. To insure proper GFCI protection, test the GFCI monthly in accordance with the manufactures instructions and if the GFCI test does not operate properly, replace the GFCI protection device.

Author’s Comment: The equipment grounding conductor serves no purpose in the operation of a GFCI protection device, and therefore it has no effect on the function of the GFCI test-button.
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Mike Holt by the way is one of the leading experts in the field of Electrical Education and Code Interpretation.

TRAINER AND INDUSTRY EXPERT
Companies across the United States have utilized the services of Mike for in-house training and expert advice. His unsurpassed speaking ability has encouraged companies such as ATT, IBM, Boeing; associations such as NECA, IAEI, IBEW, ICBO; and government agency such as Mexico, U.S. Navy, Grand Coulee Dam, etc. Mike’s appeal lies in his ability to teach a variety of subjects to individuals that have different degrees of expertise. He even has taught the NEC to the Navajo and Ute Indians, and in Spanish in Mexico!
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Anyway - now you know - as does the person with the issue...........

Sincerely,

Rod Gervais
 
dementedchord said:
well maybe one of our electrician types around here will comment to clarify this... my understanding is that they way thet work is by acting as a hair trigger to send the overloaded current to the safety... so no safety... no added protection... yes they will physicly fit the box... and operate as far as passing the AC along but will not operate in the sense of that added protection... and hense my comment... and would assume in your post that the need to mark them as not haveing a ground is indicative of this... but i am open to more data if anyone knows...
Click to expand...

A GFCI monitors the amount of current flowing from hot to neutral. If there is any imbalance, it trips the circuit. It is able to sense a mismatch as small as 4 or 5 milliamps, and it can react as quickly as one-thirtieth of a second.

If there isn't a ground - the NEC doesn't want you connecting devices to the circuit that could potentially have electricity run through the body of the device..... which is the case with any grounded equipment - so the warning is intended to notify (intelligent) people that they should only be using 2 prong (i.e. double grounded) devices on that circuit.

However = if someone does use a grounded device - and then a short occurs and they become the source to ground - the GFCI will still operate. Because that will still cause an imbalanced load to the neutral leg of the circuit.

It's just that the NEC doesn't like the idea of inviting trouble - and it's always possible that the GFCI could go bad - at which time the double grounding is still offering protection to the person using the device.

I hope that clears up your confucion on how it all works.

Rod

HOWEVER - even with a grounded device - the GFCI will still work.......
 
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